The Energy Transition in German homes

Germany has set itself the target of making its building stock virtually climate-neutral by 2050. This means improving energy efficiency in buildings as well as using a greater proportion of renewable energy for heating and hot water. The Federal Ministry for Economic Affairs and Energy is supporting the work to make buildings sustainable through a whole range of different funding programmes.

The Energy Transition is a project spanning an entire generation. It is Germany's path into a secure, environmentally friendly, and economically successful future. A lot of work has already been done. Renewable energy is now Germany’s most important energy source for electricity. However, the aim is not only to generate cleaner energy, but to use energy more efficiently. After all, there's nothing cheaper or more environmentally friendly than not having to produce so many kilowatt hours of energy in the first place.

Energy efficiency has a key role to play when it comes to buildings. Almost 40 per cent of Germany’s final energy consumption is used in buildings – mostly for heating and hot water. Over the next 20 years, half of the 19 million residential buildings in Germany will need to be modernised. We need to use this opportunity to identify and to close efficiency gaps, as well as other areas of weakness in energy efficiency in houses and flats. This will enable each and every person not only to save money, but also to help mitigate climate change.

Whether it's ceiling insulation in the basement, putting in new windows, or changing the boiler, improving energy efficiency in the home has many advantages. The first of these relates to cost. Using less energy means costs for heating and hot water also fall – and that they remain lower in the long term. Carbon emissions also decrease, helping to protect the climate and mitigate climate change. The only things to increase are all positive: the home becomes more snug and the value of the property rises once it has been modernised.

What makes a building energy-efficient?

In simple terms, an energy-efficient house is one in which adequate heating and hot water is provided using as little energy as possible. Here, the building envelope has an important role to play. This includes all of the building components that separate inside from outside – i.e. walls, ceilings and floors, as well as windows and doors. A well-insulated building envelope keeps the heat wherever it should be: it prevents it from getting inside in the summer, and stops it escaping in the winter. Part of improving the energy performance of buildings includes installing efficient heating and using this on the right setting – and, ideally, operating it using renewable energy.

The Clean Growth Strategy is yet another dubious government target

In August I wrote here about the government’s pre-announced ban on the sale of new petrol and diesel cars by 2040, and how it could turn out to be a hostage to fortune if the necessary technology fails to be developed. Today, in its Clean Growth Strategy, the government announces another dubious target: insulating a million of the leakiest homes with the aid of £3.6 billion raised through the Energy Company Obligation – which is a levy on all energy customers’ bills.

The proposal seems to work on the assumption that it is possible to insulate an old property, bringing it close to the insulation standards of a new home, at an average cost of £3,600 per home. That is hopeful, to say the least. It is possible to improve the energy performance of properties with cavity walls for something like that sum. Trouble is, nine million homes in Britain do not have cavity wall insulation – they have solid walls. It is possible to insulate them to modern standards, but for £3,600 each? You’ll be lucky. There are two ways of fitting such insulation: on the inside or on the outside of a house. To fit it internally requires every window, every door to be changed and the entire house redecorated. To fit it externally requires the whole house to be encased in cladding. As has been shown tragically once this year at Grenfell Tower, this is not something which ought to be done on the cheap. As well as increasing fire risk, badly-installed external cladding can create damp problems inside buildings by trapping moisture which had previously managed to escape through the walls.

According to the government’s own energy-efficiency quango, the Energy Savings Trust, internal insulation costs between £3,500 and £14,500 per property and external cladding between £8,000 and £22,000. So how on Earth does the government think it can be done for an average of £3,600 per home?

Even if you do spend these sums insulating a house with solid walls, it still brings you nowhere near getting it to do its bit for the target laid down in the 2008 Climate Change Act – to reduce carbon emissions by 80 per cent — compared with 1990 levels — by 2050. In order to do that, it is necessary to insulate floors, fit triple-glazing, solar panels, heat pumps and much more besides. Again, this is all possible – but at a cost.

In a demonstration project in Oxford completed in 2011, a team from Oxford Brookes University succeeded in reducing the carbon footprint of a two-up, two-down by 80 per cent. The trouble is that the project cost £90,000 – more than the house would have been worth in many parts of the country. No doubt economies of scale could bring that down to some extent, but as things stand the 2050 legally-binding carbon-reduction target remains an unlikely pipe-dream. Maybe technology will emerge to make it possible. But then again, maybe it won’t. What will the government do then? Jail itself, for failing to reach its legal target? One thing is for sure: few, if any, of those MPs who meekly voted to impose the 2050 Climate Change target on the country without having any idea as to how it would be achieved will still be around to face the consequences.